1. Field of the Invention
The present invention relates to an apparatus for cutting and removing a package material from a packaged object, and more particularly to an apparatus for cutting and removing a sheet-bag-like package material from a packaged object which comprises a stack of can ends packaged in the package material.
2. Description of the Related Art
Can ends are attached to open-top cans such as beer cans, soft drink cans or the like. The can ends are superimposed in a cylindrical stack, packaged in a sheet-bag-like package material, and then delivered to a beverage producing process. In the beverage producing process, the package material is removed from a packaged object including a cylindrical stack of can ends, and one of the can ends, at a time, is supplied to an open-top can which has been filled with beverage such as beer. Then, the can end is placed over the open-top of the cylindrical can and attached thereto by seaming.
U.S. Pat. No. 5,275,524 discloses an apparatus for cutting and removing a package material from a packaged cylindrical object including a cylindrical stack of can ends. The disclosed apparatus comprises a feed unit having a pusher for feeding a packaged object in a longitudinal direction, one by one, by a pusher, a package cutting unit for forming, under vacuum, a loop-like slackened portion of the package material in a longitudinal direction of the packaged object and for cutting open the slackened portion, a package removing unit for removing the cut-opened package material by a pair of rollers from the package object which has been supplied thereto by the pusher having a constant stroke, and a delivery unit for delivering the stack of the can ends from the package removing unit to a delivery conveyor.
The disclosed apparatus is designed to handle only such a packaged object, having an approximately constant length, which is formed by stacking a predetermined number of flat can ends which adhere closely to one another. Therefore, the pusher for pushing the trailing end of the packaged object has a constant stroke. In the case where the respective packaged objects have variations in number of can ends and are elastic due to their complicate shape of the can ends, when the packaged object which has been cut open is fed into the removing unit, the Gap is formed between the forward end of the packaged object and the forward-side stopper fixedly provided on the apparatus, or the packaged object is excessively compressed by the pusher.
In the former case, since the packaged object cannot be properly supported by the forward-side stopper and the rear-side stopper, the can ends are scattered in pieces after removing the package material. In the latter case, the can ends are also scattered in pieces due to restitution of the compressed can ends after removing the package material.
Further, the disclosed apparatus cannot cut open the package material having a folded portion, so-called "flap fold" at one end thereof. To be more specific, as shown in FIG. 8A, a packaged object 1 is formed by inserting a stack of can ends 3 into a sheet-bag-like package material 2 whose open end is folded back, and then sticking an adhesive tape 4 onto the folded portion and the circumferential surface of the package material 2 as shown in FIG. 8B. The disclosed apparatus cannot deal with the packaged object 1 as shown in FIGS. 8A and 8B because it is difficult to form an upwardly slackened portion at the upper portion of the package material under the vacuum created by a suction device due to overlap of the folded portion and to thus cut open the folded portion by the cutter.
Furthermore, the disclosed apparatus is designed to handle only relatively short packaged objects. In case of the short packaged object, the can ends are not scattered in pieces when discharged from the removing unit. However, in case of the long packaged object, the can ends are likely to be scattered in pieces at the central portion thereof when discharged from the package removing unit.